Glossary
GL-4
April 2001 8000-A2-GB26-50
MVL modem
An endpoint (customer premises) modem that provides high-speed Internet or corporate
LAN access over twisted-pair copper lines using MVL technology.
NAP
Network Access Provider. The provider of the physical network that permits connection of
service subscribers to NSPs.
NHR
Next Hop Router. The next router IP address to any given destination.
NMS
Network Management System. A computer system used for monitoring and controlling
network devices.
NSP
Network Service Provider. A local telephone company or ISP that provides network services
to subscribers.
NTP
Network Time Protocol. A method for maintaining accurate local time with respect to radio
and atomic clocks on the Internet.
NVRAM
Non-Volatile RAM.
OCD
Out of Cell Delineation. When operating in direct mode, an OCD event is declared if seven
consecutive cells have header error control violations.
OpenLane DCE
Manager
A proprietary network management program used with HP OpenView that helps a network
administrator manage SNMP devices.
packet
A group of control and data characters that are switched as a unit within a communications
network.
PDU
Protocol Data Unit. A message containing protocol-specific information.
PING
Packet InterNet Groper. Used for testing and debugging networks, PING sends an echo
packet to the specified host, waits for a response, then reports the results of its operation.
Used as a verb, to PING means to use the program to verify the accessibility of a device.
The PING program is supported from both the DSL and MCC cards.
POTS
Plain Old Telephone Service. Standard telephone service over the PSTN with an analog
bandwidth of less than 4 kHz.
POTS Splitter
A device that filters out the DSL signal and allows the POTS frequencies to pass through.
PPP
Point-to-Point Protocol. as specified by Internet RFC 1661.
Proxy ARP
Proxy Address Resolution Protocol (ARP). A technique for using a single IP address for
multiple networks. A device responds to ARP requests with its own physical address, then
routes packets to the proper recipients.
PSTN
Public Switched Telephone Network. A network shared among many users who can use
telephones to establish connections between two points. Also know as dial network.
RADSL
Rate Adaptive Digital Subscriber Line. A technique for the use of an existing twisted-pair
line that permits simultaneous POTS and high-speed data communication at adaptive
symmetric and asymmetric rates.
rate adaption
The ability to automatically adapt when the port speed is lower than the line speed.
ReachDSL
A subscriber line technology providing up to 1 Mbps throughput. Compliant with ANSI
T1.417, ReachDSL guarantees a minimum rate of 256 kbps at 18 kft.
Router
A device that connects LANs by dynamically routing data according to destination and
available routes.
Routing Table
A table used by a node to route traffic to another node in the multiplexer network.
RTT
Round Trip Time.
RTU
Remote Termination Unit. A DSL device installed at the customer premises.